Reaction of BiCl3 with 2-(2-hydroxy-3-methoxyphenyl)benzimidazole (HL) in tetrahydrofuran (THF) under reflux gave mononuclear complex of formula [Bi(HL)2Cl3·H2O]. The binding interaction of the complex with bovine serum albumin (BSA) was investigated using the fluorescence quenching method. The experimental results showed that the complex could bind to BSA in the proportion of about 1:1. The binding reaction was spontaneous and hydrophobic force played major role in the reaction. The binding of the complex to BSA could change the microenvironment and conformation of BSA.
